oik-external-link-warning v1.0.0-alpha.0503 supports displaying a warning message when a visitor hovers over or clicks on a mailto:
link.
Email: oikplug@oik-plugins.com
Hover over the link to see the warning message. Click on the link to see a popup message box.
The text of the warning message should be something like “Email communications are not secure” followed by further disclaimers that “for this reason your company cannot guanrantee the security of the email, its contents or that it remains virus free once sent.”